collins



E. F. COLLINS. ELECTRIC HEATING APPARATUS. IAPPLICATION FILED SEPLZS. 1919.

1,343,996. PatentedJune 22,1920.

2 SHEETS-SHEET I.

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Inventor: Edgar F Col libs,

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E. F. COLLINS.

ELECTRIC HEATING APPARATUS.

APPLICATION FILED sums. 1919.

1,343,996. v Patented June 22, 1920.

2 SHEETS-SHEET 2.

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Edgar F Collins, H M

His Ylttorneg.

- UNITED STATES PATENT OFFICE.

EDGAR F. COLLINS, OF SCHENECTADY, NEW YORK, ASSIGN OR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW- YORK.

ELECTRIC HEATING APPARATUS.

Specification of Letters Patent.

Patented J une 22, 1920.

Application filed September 23, 1919. Serial No. 325,656.

To all whom it may concern:

Be it known that I, EDGAR F. COLLINS, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Heating Apparatus, of which the following is a specification.

My invention relates to improved apparatus for electrically heating articles by passing a current .of electricity therethrough. More particularly my invention relates to an apparatus for electrically heating rivets or the like which, after heating, are removed from the apparatus and upset in the work in any desired manner. My invention is not, however, limited as to the particular article to'be heated. It is adapted, for example, to heat bolt stock which is to be upset to form heads for the bolts, as well as for electrically heating small forgin or other articles as will be obvious to those skilled in the art to which the invention relates.

-An object of the invention is to produce at, a moderate cost a reliable apparatus which is simple and rugged in construction,

and the operation of which is so simple as to enable a uniform, product to be secured without the employment of skilled labor for the operation'of the apparatus. The invention resides in certain combinations of parts and features of construction designed to accomplish the aforesaid objects.

In the accompanying drawings which illustrate several embodiments of my inven-' tion, Figures land 2 are perspective views showing the front and rear construction of one embodiment of my invention; Fig. 3 is a side View showing a modified construction of the operating mechanism; Fig. 4; is a diagrammatic representation of. a modification comprising a plurality of independentsecondary circuits; Fig. 5 is a diagrammatic representation of a modificationinvolving two secondary coils in series, and Fig. 6 is a perspective view with parts broken away, showing one practical embodiment of the arrangement comprising two secondary coils in series. 7

Referring to Figs. 1 and 2 of the drawing, a shell-type transformer is illustrated provided with a primary winding 1 on the center leg of the core, the two outsidelegs 2 and 3 being left unwound. These legs are represented in the drawing as covered with a layer of tape which is provided merely for the purpose of assisting in holdmg the laminations together prior to their complete assembly in the device. Electrodes 4; and 5 are mounted respectively on conducting bars 6 and 7 preferably made of copper which are respectively movable'in the windows of the transformer core. These bars are mounted for independent pivotal movement about a shaft 8, mounted in members 9 and 10, mounted on the frame carryingthe transformer core. The bars 6 and 7 are connected by curved laminated conductors 11 and 12 secured to the bars adjacent the pivotal points. The members 9 and 10 are secured to the frame of the apparatus which is represented as an angle iron structure comprising rear legs 13 and 14c and front legs 15 and 16. The transformer core is clamped in this frame by the bolts 17,

the pan 22 may be mounted in any desired position. The conducting member 20 is supported by members 23 and 24, secured to the frame. of the apparatus.

The conducting bars 6-and 7 are shown as arranged to be independentlyoperated by pedals 25 and 26 mounted on a rod 27 secured to the front legs 15 and 16 of the frame. The pedals are connected'to the arms 6 and? by rods 28 and 29 in which insulating joints 30 are provided. A member 31 secured to the legs 15 and 16 of the frame not only acts to brace the frame but also acts as a stop for the pedals 25 and 26 to limit their upward movement which corresponds to a, downward movement of the electrodes 4 and 5. 6

The movable electrodes 4 and 5 are provided with curved contact faces 32 and 33 to enable articles of various lengths to be interposed between them and the conducting member 20.

The conducting bars 6 and 7 constitute a secondary winding for the transformer of which the winding 1 is the primary. \Vhen the articles 18 and 19 are interposed between the movable electrodes and the conducting member 20 the secondary circuit is completed as follows: From the bar 6 to the electrode 4., article 18, conducting member 20, article 19, electrode 5, bar 7 and flexible conductors 11 and 12 back to the bar 6.

The primary winding 1 is provided with a plurality of taps leading to a switch 31 mounted on a panel secured to the rear legs 13 and 11 of the frame. This switch permits the number of turns in the primary winding to be varied for the purpose of adjusting the current induced in the secondary winding in accordance with the size and character of the articles to be heated.

Itis obvious that various forms of switches for controlling the transformer taps may be provided if desired, whether of the type shown or of the drum controller type.

The operation of the apparatus is as follows: The circuit primary winding 1, having been closed to any convenient source of alternating current, the operator depresses pedals and 26 and inserts the articles 18 and 19 which are to be electrically heated. Upon the completion of the secondary circuit by lowering the movable electrode into contact with the article last inserted, a heavy current is induced in the secondary winding which quickly heats the articles to the desired value. As soon as one of the rivets becomes heated to the desired value the corresponding electrode is raised, a new article substituted, and the circuit again closed. The heating current passes through the articles to be heated in series and each article serves as a ballast resistance for the other, so that danger of burning the articles is avoided. The curved contact faces 32 and of the movable electrodes l and 5 permit a good'contact to be made with the upper ends of the articles to be heated for any length of article within the capacity of the machine. The curved laminated conducting members 11 and 12, being composed of very thin copper laminations, readily flex and twist to permit independent movement of the electrode carrying bars 6 and 7.

Fig. 3 illustrates a modification in which the operating lever 35 is arranged as a bell crank lever operated by the hand or foot pedal 36, projecting toward the side of the machine. This bell crank lever is connected through a loose connection 37 to a member 38, bolted to the bar 6 adjacent the pivot point thereof. This arrangement makes it unnecessary to insulate the lever 85 since the pivot point of the bars 6 and '7 connected by the members 11 and 12 are at the neutral point of the secondary winding and no provision is made for insulation at this point either in the arrangement shown in Figs. 1 and 2 or that shown in Fig. 3. It will be understood that the arrangement shown in Fig. 3' comprises a plurality of bars, operating levers and movable electrodes similar to the arrangement shown in Fig. 1.

It is obvious that the invention is not limited to an arrangement in which there is but a single electrode-carrying bar mounted in each core window. F ig. 4: diagrammatically represents a construction in which four such bars, 41, d2, a3 and Tel, are pivoted about a rod -15 and connected by flexible conductors M3 and 47 in two independent secondary circuits; The articles to be heated are represented by dotted lines and are interposed between the movable electrodes d8, 19, 50 and 51, and the conducting members 52 and 53. In this figure the transformer core is represented in section and certain parts are omitted to show the arrangement more clearly. It will be understood that the movable electrodes are arranged above the conducting members 52 and 53 as in Figs. 1 and 2. One series circuit through two of the articles to be heated comprises the bar 41, electrode T8, conducting member 52, electrode 50, bar l3 and flexible connector 46. The other series circuit comprises the bar 42, electrode 49, conducting member 53, bar 4a and flexible connector 4:7. It is obvious that this arrangement increases the capacity of the machine in that both of the heating circuits may be used simultaneously when desired. The bars 41 and 42 and the bars 13 and 44 may be mounted either side by side, as shown in Fig. 4t, or one above the other as desired. The connectors 16 and 4:7 are represented as flexible cables in Fig. 4, although the curved laminated connector shown in F 1 and 2 is the preferred type of connection. I

Fig. 5 diagrammatically illustrates an arrangement in which two secondary coils, connected in series through the articles to be heated, are utilized. The secondary coil closely surrounds the primary coil 1 on the center leg of the core 61 which is shown in section. This secondary winding is preferably constructed of a bar of copper having crossed connections 62 and 63 leading to stationary electrodes or conducting members 64: and 65. The movable electrodes 66 and 67 are mounted on copper bars 68 and (59 respectively as in the arrangement shown in Figs. 1 and 2, these bars being connected by the flexible conductor 68. The movable electrodes 66 and 67 are in practice arranged above the electrodes (3 1 and (35 as in the arrangement shown in Figs. 1 and 2. Upon completion of the circuit through the articles paratus.

62 and 63. In this figure certain parts are.

shown in section and certain parts omitted while the apparatus is represented as turned through an angle of about 90 from the position in which it is actually used in order to enable the construction and connections to be shown more clearly. The movable electrodes 80 and 81, between which and the stationary conducting member 82 the articles to be heated are adapted to be interposed, are mounted respectively on conducting bars 83 and 84, and pivoted on a rod 85 for independent movement as in Figs. 1 and 2. The stationary secondary coil is preferably made of copper bar having sides 86 and 87 located in the windows of the core 88. The pivoted end of the conducting bar 83 is connected by a laminated conductor 90 to one side, 87, of the stationary coil, the other side, 86, of which is connected by the flexible laminated conductor 89 to the conducting bar 84:. It will be apparent that this arrangement differs from the arrangement shown in Fig. 5 merely in providing the cross connection at the rear instead of at the front of the ap- This arrangement is somewhat simpler to construct than the arrangement involving the cross connections of Fig. 5. It will be apparent that the bars 83, 86 and 8 1, 87 may be mounted one above the other instead of side by side as shown in Fig. 6, if desired.

lVhat I claim as new and desire to secure by Letters Patent of the United States, is-

1. In an apparatus for electrically heating articles of the class described, a transformer winding comprising a plurality of independently movable conducting bars carrying electrodes, and a conducting member between which and the movable electrodes the articles to be heated are adapted to be interposed whereby a series circuit may be completed through said winding and the articles to be heated.

2. In an apparatus for electrically heating articles of the class described, a transformer comprising a stationary primary winding and a secondary winding comprising a plurality of independently movable conducting bars, electrodes mounted on said bars and conducting means between which and the movable electrodes the articles to be heated are adapted to be interposed, said conducting means being arranged to complete a series circuit through said secondary winding and a plurality of articles to be heated.

3. In an apparatus of the class described, a secondary winding comprising a pair of pivoted bars carrying electrodes, a curved laminated flexible conducting member'secured to said bars adjacent the pivot points and a conducting member between which and the movable electrodes articles to be electrically heated are adapted to be interposed.

1. In an apparatus for electrically heating articles of the class described, a shell type transformer having a primary winding on the center leg, a plurality of bars arranged for independent movement in the windows of said core and adapted to act as parts of the secondary winding of said transformer, conducting means connecting said bars while permitting independent movement thereof, electrodes mounted on said bars and a conducting member between which and said electrodes the articles 7 to be heated are adapted to beinterposed arranged to complete the circuit of said 

